Transmission Housing

ABSTRACT

A drive unit having a drive gear rotatable about a drive-gear axis mounted on an angle transmission having a housing formed unitarily of one piece with a throughgoing passage centered on a longitudinal axis, a plurality of substantially planar outer faces each extending substantially parallel to the axis, one of the outer faces bearing flatly on the drive unit, a transverse bore opening at and extending between the one face and the passage along an axis transverse to the longitudinal axis, and a plurality of undercut grooves extending longitudinally the full length of the housing and opening at least at the one outer surface. Each of the grooves is substantially narrower at the respective outer face than inward therefrom measured in a direction transverse to itself and parallel to the respective outer face. A main gear is rotatable in the passage about the longitudinal axis and a drive gear is rotatable about the transverse axis in the transverse bore in mesh with the main gear. A plurality of bolts seated in the drive unit each have an enlarged end in a respective one of the grooves of the one face so that the bolts clamp the drive unit and housing together parallel to the transverse axis.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national phase of PCT applicationPCT/AT93/00076 filed 3 May 1993 with a claim to the priority of Austrianapplication A 903/92 filed 4 May 1992.

FIELD OF THE INVENTION

The invention relates to a transmission housing, in particular for anangle, e.g. worm-type, transmission that has a throughgoing inparticular cylindrical passage which runs longitudinally of an extrudedprofile forming the housing, that has outwardly open grooves that openat planar outer faces of the housing that in turn are inclined to eachother preferably at 90°, and that has starting from one of the planarouter faces a bore which is formed in the housing and whose surfacejoins the surface of the passage extending longitudinally through theextruded profile.

BACKGROUND OF THE INVENTION

A housing of this type is known from German published patent application2,944,398 where the outer face of the housing body has threelongitudinally extending recesses for receiving threaded bolts thatextend all the way through and secure two housing covers with eachother. The walls of the recesses diverge outwardly so that theconnecting bolts can be inserted transversely to their longitudinal axesinto the recesses. Problems are encountered with such a housing when thehousing is to be secured to a machine or when it is to be mounted on aflange motor.

OBJECT OF THE INVENTION

It is therefore an object of the present invention to provide andimproved transmission housing.

SUMMARY OF THE INVENTION

The invention proposes a solution in that the grooves are undercut, inparticular to be T-shaped, trapezoidal, or dove-tail-shaped, and themouths of the grooves at the outer faces are the groove regions ofminimal width. This constructions makes it possible to secure thehousing on a machine by screws whose heads are inserted in the undercutgrooves so that the housing can sit with the respective planar outerface flat against the support surface of the machine. Similarly a motorcan be flange mounted, with its flange sitting flush on the outer face.

In a further embodiment of the housing according to the invention anangle, preferably a worm-drive, transmission, can be provided with theabove-described housing.

It is known from above-named German published application 2,944,398 toform the bore for receiving the worm as a throughgoing bore. Thethroughgoing bore is thus closed at both of its ends by covers whichposition in the bore the roller bearings provided for rotatablysupporting the worm shaft. The outer races of the roller bearings thuscontact the bore wall and are supported from the side by the respectivecover. The inner race of each roller bearing bears against an end faceof the worm body. In this arrangement there are two locations in thebore to be sealed. In addition the bore needs to be machined in order tomount the roller bearings properly by means of their outer races.

It is another object of the invention to simplify this system. This isachieved in an angle, in particular in a worm-drive, transmission of theabove-described type where the shaft carrying the drive gear (worm) hasa bearing, in particular a roller bearing provided in a housing that isflanged to the extruded profile with the flange lying on one of that oneof its outer faces from which the bore extends and where the housingholding the bearing is the housing of a flange motor whose rotor shaftcarries on its free end the drive gear (the worm) or that the drive-gearshaft traverses the bearing housing and the second bearing, inparticular a needle bearing, is arranged in the housing formed by theextruded profile in a housing bore formed as a blind bore. Thisarrangement has the advantage that at least one bearing of the drivegear or the worm is situated in a separate housing and can therefore bemachined independently of the transmission housing so that thetransmission housing needs no further machining at least with respect tomounting the worm except for the formation of the bore which is formedas a blind bore. When the housing for the bearing is also the housing ofa flange motor, the second bearing location is thus in this housing andis formed by the bearing for the rotor shaft. If however the shaft ofthe drive gear passes through the bearing housing and the shaft end thatis outside the bearing housing serves a drive purpose, the secondbearing location of the drive-gear shaft is aligned with and forms acontinuation of the blind bore. The bearing can be a needle bearing.

As far as the bearings for the main gear are concerned, according to aparticular feature of the invention a bearing, in particular a roller,e.g. ball, bearing is provided to each side of the main gear, eachbearing being mounted in a sleeve set in the throughgoing passage of theextruded profile or this sleeve serves as the bearing. Thus in order tosupport the main gear on bearings no special machining is necessary. Thebearings are held by special sleeves which are inserted in thethroughgoing passage of the extruded profile. This has the advantagethat the outer diameter of the sleeves can be fitted to the actualdiameter of the throughgoing passage of the extruded profile, withoutregard to wear of the extruding die or thermally created changes of theextruding die.

It is of particular advantage when the roller bearings are also used toretain the sleeves in the housing. To this end the outer race of thebearing bears on a shoulder of the sleeve and the inner race of theroller bearing bears on a spring ring fitted in an annular groove of themain-gear shaft. The sleeve can have an outer flange that contacts thatface of the extruded profile from which the throughgoing passageextends. These are the end faces of the housing formed by the extrudedprofile.

To retain the sleeves according to a particular embodiment of the objectof the invention a plurality, in particular three, tie bolts areprovided, each traversing two axially aligned bores in the sleeves, toclamp the sleeves against each other.

To seal the bore holding the tie bolts it is advantageous to providewashers of elastically deformable material, in particular plastic, whichare arranged between either the bolt head or the bolt nut and theadjacent outer face of the sleeve. When the sleeves are tightenedtogether by tightening the bolt nuts material of the washers enters intothe screwthreads so that the screwthreads are sealed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described more closely below with reference toembodiments shown in the drawing. There is shown in:

FIG. 1 a cross-section through an embodiment of a transmission housing;

FIG. 2 a transmission housing as in FIG. 1 but for a transmission which,unlike FIG. 1, is not driven by a flange-mounted motor but which isdriven via other means such as gears or belt pulleys;

FIG. 3 is a section taken along line III--III of FIG. 1;

FIG. 4 is a modified version of the FIG. 3 embodiment in a view likeFIG. 3;

FIG. 5 is also a modified embodiment in a view like FIG. 3;

FIG. 6 is an angle drive with bevel gearing in a view like FIG. 3; and

FIG. 7 is a section taken along line VII--VII of FIG. 6.

SPECIFIC DESCRIPTION

The transmission housing is generally indicated in the drawing at 2.According to FIGS. 1 to 5 it serves for holding a worm drive. It canalso generally serve for another angle drive, e.g. a bevel-geartransmission (FIGS. 6 and 7) or a face-gear transmission. The housing isformed as an extruded profile and has a laterally closed, in particularcylindrical passage 1 extending longitudinally through the profile. Thehousing 2 is formed externally with grooves 3 that open at planar outerfaces 4, 5, 6, and 7 of the housing. Each of the outer faces forms acorner with an adjacent outer face at an angle here of 90°. The housing2 thus forms a prism with a four-sided, in particular rectilinear,footprint. A bore 8 enters the housing from the planar outer surface 7of the housing. In special cases this bore 8 is blind. The inner wallsurface of the bore 8 joins the surface of the passage 1 longitudinallytraversing the extruded profile. The grooves 3 are undercut and have inthe illustrated embodiment T-shapes as shown on surfaces 4, 5, and 6 ortrapezoidal shapes as shown on surface 7, and can also be of L-shaped sothat each of the openings 9 at the outer faces 4, 5, 6, and 7 of eachgroove 3 is the narrowest part of the groove cross section. The grooves3 can receive the heads of bolts with which the housing 2 is secured toa machine or the like.

The main gear 10 of the transmission is arranged in the passage 1 andthe small gear 11 (worm or bevel gear) is arranged in the bore 8 openingat the outer face 7 of the extruded profile. A bearing in the form of asingle roller bearing 13 in a housing 14 or as in FIG. 6 two bearings 13are provided for the shaft 12 carrying the gear 11 (worm or bevel gear).A housing 14 is flanged to the extruded profile. The flange 15 of thehousing 14 contacts that outer face 7 of the extruded profile at whichthe bore 8 opens.

In the embodiment of FIG. 1 the housing 14 of the bearing is the housingof a flange motor 16. The output shaft 17 of the flange motor 16 has onits free end the gear 11 (worm). In the embodiment according to FIGS. 2and 6 the gear shaft traverses the bearing housing 14 so that drivetorque is applied to the shaft stump projecting from the bearing housing14. The second support bearing of the gear shaft 12 is in the case of aworm drive (FIG. 2) in the housing 2 and is preferably formed as aneedle bearing 18. The needle bearing is fitted in a blind bore alignedwith the bore 8 of the housing. According to the embodiment of FIG. 6the gear 11, which is a bevel gear, is mounted on the shaft 12 in anoverhung manner.

A roller bearing 19 can be provided to each side of the main gear 10 ofthe transmission to support it. The main gear 10 can also as not shownbe supported on each side in a journal.

In the embodiment according to FIGS. 3 and 4 each of the roller bearings19 for supporting the main gear 10 is arranged in a sleeve 20 fitted inthe passage 1 of the extruded profile.

In the embodiment according to FIGS. 5 and 6 there are also rollerbearings 32 to both sides of the main wheel 1, with their outer races 33each set in a cutout of the passage 1 of the housing 2 and bearingagainst a shoulder 34 at an inner end of the cutout.

In the embodiment according to FIG. 3 each of the sleeves 20 is held viathe respective roller bearing 19 in the passage 1 so that the outer race21 of the roller bearing contacts a shoulder 22 of the sleeve 20 and theinner race 23 of the roller bearing contacts a spring ring 25 set in agroove of the main-gear shaft 24.

In a modified embodiment shown in FIG. 4 several, here three, tie bolts26 are provided to retain the sleeves 20. Each tie bolt traverses twoaligned axial bores in the sleeves 20. The tie bolts clamp the twosleeves 20 toward each other.

Washers 28 of elastically deformable material, in particular plastic,are provided to outwardly seal the axial bores 27. These washers 28 areeach mounted between the respective bolt head 29 or nut 30 and theadjacent outer face 31 of the sleeve 20. When the nuts 30 are tightenedthe washers 28 are compressed so that material of the washers is forcedinto the threads of the tie bolts 26 or of the nuts 30 to seal thisscrewthread.

The blank for the transmission housing can be made simply by cutting thehousing from the extruded profile at the necessary length. Aside fromforming a bore for receiving the worm and if necessary its bearings orin a bevel-gear transmission the bore for the bevel gear, the housingneeds no further machining.

I claim:
 1. In combination with a drive unit having a drive gearrotatable about a drive-gear axis, an angle transmission comprising:ahousing formed unitarily of one piece with a throughgoing passagecentered on a longitudinal axis, a plurality of substantially planarouter faces each extending substantially parallel to the axis, one ofthe outer faces bearing flatly on the drive unit, a transverse boreopening at and extending between the one face and the passage along anaxis transverse to the longitudinal axis, and a plurality of undercutgrooves extending longitudinally the full length of the housing andopening at least at the one outer surface, each of the grooves beingsubstantially narrower at the respective outer face than inwardtherefrom measured in a direction transverse to itself and parallel tothe respective outer face; a main gear rotatable in the passage aboutthe longitudinal axis; a drive gear in the transverse bore in mesh withthe main gear and rotatable about the transverse axis; and a pluralityof bolts seated in the drive unit and each having an enlarged end in arespective one of the grooves of the one face, the bolts clamping thedrive unit and housing together parallel to the transverse axis.
 2. Thetransmission defined in claim 1 wherein the slots are T-slots.
 3. Thetransmission defined in claim 1 wherein the slots are of trapezoidalshape.
 4. The transmission defined in claim 1 wherein the outer facesmeet at corners and form angles of substantially 90° at the corners. 5.The transmission defined in claim 1 wherein the drive unit includes amotor.
 6. The transmission defined in claim 1, further comprisingabearing in the bore of the housing supporting the drive gear forrotation about the transverse axis.
 7. The transmission defined in claim1 wherein the transverse bore extends generally tangentially of thepassage and is a blind bore.
 8. The transmission defined in claim 1,further comprising:a main shaft extending along the longitudinal axisand carrying the main gear; and a pair of bearings in the passageflanking the main gear and having outer races bearing on the housing andinner races mounted on the main shaft.
 9. The transmission defined inclaim 8 wherein the passage is generally cylindrical and has axiallyoppositely directed shoulders against which the outer races bearaxially.
 10. The transmission defined in claim 8, further comprisingapair of sleeves flanking the main gear, set in the passage, and eachforming a seat for a respective one of the outer races of the bearings.11. The transmission defined in claim 10 wherein each of the sleeves isformed with a shoulder bearing axially on the respective outer race. 12.The transmission defined in claim 11 wherein the shoulders are directedaxially outward, the transmission further comprisingtie bolts extendingparallel to the longitudinal axis in the passage and each having one endbearing axially inward on one of the sleeves and an opposite end bearingaxially oppositely inward on the other sleeve.
 13. The transmissiondefined in claim 11 wherein the shoulders are directed axially inward,the transmission further comprising:tie bolts extending parallel to thelongitudinal axis in the passage and each having one end bearing axiallyinward on one of the sleeves and an opposite end bearing axiallyoppositely inward on the other sleeve; and abutment rings set in themain shaft axially immediately outward of and bearing axially outward onthe respective inner races.